In oil seal apparatuses used for casings containing equipment, lips are provided to prevent the entry of dust, rainwater and muddy water which might otherwise contact the equipment.
Especially in the front portion of the cylinder block of an internal combustion engine, the crankshaft projects and the crankshaft pulley is fixed to the projection. Therefore, an oil seal fitted between the cylinder block and the crankshaft is more liable to be exposed to dust, rainwater and muddy water. The conventional oil seal comprises a main lip for oil sealing and a dust lip to prevent the entry of dust etc. However, this known seal has not been able to prevent the entry of rainwater or muddy water which runs down along the cylinder block or crankshaft pulley.
Accordingly, an object of this invention is to provide an oil seal apparatus effective for preventing the muddy water etc. which runs down along the equipment casing from entering into the oil sealed portion of the casing.
Another object of this invention is to provide an oil seal apparatus effective for preventing the muddy water etc. which runs down along a rotating member, such as the crankshaft pulley fixed to the shaft outside the casing, from entering into the casing.
A further object of this invention is to provide an oil seal apparatus especially suited for use in the front portion of the cylinder block of an internal combustion engine.